So, I have this transformer to drive a pair of 7591 tubes in a guitar amp I'm building. It was given to me, as it was going to be thrown in the trash. It seems like a nice piece of iron, but I can't identify the numbers on it. I tried to cross reference it with no luck. If any of you more experienced guys can point me in the right direction as far as the numbers, it would really be appreciated.

Anyway, on the bell it reads:

C56 34E
1005417

And on the winding, there's a 37W31 stamped in ink. Here's some pics...